R(+)-N-propargyl-l-aminoindan (“R-PAI”), also known as rasagiline, has been reported to be a selective inhibitor of the B-form of the enzyme monoamine oxidase (“MAO-B”) and is useful in treating Parkinson's disease and various other conditions.
Rasagiline mesylate is approved for treating Parkinson's disease either as monotherapy or as an adjunct with other treatments. See, e.g. AGILECT®, Physician's Desk Reference (2007), 61st Edition, Thomson Healthcare.
A synthesis of rasagiline is disclosed in U.S. Pat. No. 5,532,415 in which example 3 describes recovery of rasagiline base as an oil after chromatographic separation. The other synthetic examples in U.S. Pat. No. 5,532,415 show rasagiline salt preparation from its crude form or its racemic form which is further reacted with appropriate acids to form pharmaceutically acceptable salts.
In pharmaceutical compositions, crystallinity is a desirable property in an active pharmaceutical ingredient. Crystal substance allow for ease in processing and formulating into most types of pharmaceutical dosage forms. Rasagiline base may be isolated in a crystalline form.
The solid rasagiline base prepared by crystallization is typically not completely “dry” and does contain solvent. There is a need for a method suitable for drying solid rasagiline base from solvent while minimizing loss of yield due to sublimation.